Self-lubricating pump



Feb. 28, 1967 s. w. SMITH 3,306,225

SELF-LUBRI CATING PUMP Filgd July a, 1964 5 Sheets-Sheet l 91 89 gal [T71 se 21'* 56 4l /ms i] 39 @my 72 r6V *Il 64 ni 32 /9 I8 Il IH l l430/ V 84 L V 82 595 al l- `1N VENTOR SYLVEXTER W ASI/141271 TIRNEYS Feb. 28, 1967 s. w. sMlTH 3,306,225

SELF-LUBRICATING PUMP Filed July 8, 1964 5 Sheets-Sheet 2 INVENTOR ,SYLVESTER W SMITH TTRNE )Ik Feb. 28, 1967 s, w, SMrrH 3,306,225

vSELF-LUBRICATING PUMP Filed July 8, 1964 Y 5 Sheets-Sheet 5 Il HU 43 l \v I Z0" 4a 508 D C'Illlll 43@ 0 244m) 5o l my l un :HH I n u 3 v L n 50a *Hlm I 50a d4' v -ll4 "Ilmmnlmrlfrl[Nimm: iHH

3@ 3 43 (24 25 43 w "w u INVEMOR SYLVESTER. WAM/TH ATTORNEY Feb. 28, 1967 Filed July 8, 1964 `5 Sheets-Sheet 4 5o 5o U um; l/l IH H ||[HumpHumlmlmul 'Hf l JNVENTOR. SYLVEJTLR WSMITH JITTORIVEY" s. w. SMITH 3,306,225

SELF-LUBRICATING PUMP Feb. 28, 1967 s. w. SMITH 3,306,225

SELF-LUBRI CATING PUMP Filed July 8, 1964 5 Sheets-Sheet 5 INVENTOR SH wis'TR ffy/MH ATTORNEYS United States Patent Otice 3,306,225 Patented Feb. 28, 1967 3,306,225 SELF-LUBRICATNG PUMP Sylvester W. Smith, 1961, Joseph Court, Decatur, Ga. 30032 Filed July 8, 1964, Ser. No. 381,057 4 Claims. (Ci. 103-126) This invention relates to pumps, and is more particularly concerned with a self-lubricating pump having automatic means for compensating for wear.

In present day hydraulic pumps, severe demands are made on the pumps in operation. The pumps must be capable of continuous operation for long periods of time without breakdown; and, the pumps must be able to withstand severe, sudden, or shock loads without deleterious elects to the pump or its bearings. The extremely high pressures used in present day hydraulic systems require pumps to deliver an extremely high pressure, and, of course, a high pressure within the pump causes greater loading on the bearings of the pump, leadin-g to a rapid breakdown if the bearings are not properly lubricated at all times. Also, it is quite desirable to have some selfcompensating means for the wear within the pump.

Previous designed pumps have in-cluded various internal lubricating means to provide lubrication at some or all of the bearings within the pump. These lubricating systems have usually been quite complex and diflicult to manufacture, nor have they been completely efficient in their operation. Self-compensating wear adjustments have been relatively simple, but they have not achieved the desired purpose due to unreliability of the materials and the particular arrangement of the parts. One of the principal diiculties of these pumps has been due to the entrance of air int-o the hydraulic system. As is well known, air or other gas within the hydraulic system causes a sponginess to the operation of various hydraulic equipment, and is otherwise quite undesirable.

The pump of the present invention overcomes the above mentioned and other diculties by providing selflubricating means including passages from the output, or high pressure side, of the pump to the various bearing surfaces of the pump, to provide lubrication under pressure for the pump; and, the pressure of the lubrication system will be directly proportional to the operating pressure of the pump, thereby maintaining good lubrication to all bearings at all times during the operation of the pump. The lubrication system is so designed that the pressures in the pump will always be greater than atmospheric pressure. As a result any leakage within the pump will be exhausted to the outside of the pump rather than allow air to enter the pump. The pressure on both sides of all bearings is equal to keep a good and adequate lm of oil on each bearing.

A wear compensation means is provided. The wear compensation means is associated with the lubrication system in such a manner that the higher the operating pressure of the pump the more firmly the wear compensating means is pressed against the operating part of the pump. Th-ese and other features and advantages of the present invention will become apparent from the following specication when taken in conjunction with the accompanying drawings in which:

FIG. l is a cross-sectional View taken along the center line of the pump shafts.

FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. 1.

FIG. 3 is a plan view of the face plate viewed from,

inside the pump.

FIG. 4 is a cross-sectional view taken substantially along the line 4 4 in FIG. 3.

FIG. 5 is an enlarged prospective view of one of the seals to be used in the pump of the present invention.

port 26 extending from outside the FIG. 6 is a plan view of the wear plate as viewed from outside the pump.

FIG. 7 is a side elevational view of the wear plate shown in FIG. 6.

FIG. 8 is a plan view of the wear plate as viewed from inside the pump.

FIG. 9 is an exploded, perspective View of the pump, some parts being omitted for clarity.

FIG. l0 is a perspective view of the wear plate with a schematic presentation of the passageways within the face plate.

Referring now more particularly to the drawings and to that embodiment here chosen by way of illustration, there is shown a subsantially conventional gear pump including a body 10 having an opening 11 therein, to receive a pair of complementary gears 12. The opening 11 is somewhat elongate and has circular end portions, the arrangement being such that the complementary gears 12 can be placed within the openin-g 11, the gears being enmeshed; and one of the gears will be -concentric with each of the circular end portions of the opening 11. From the wall 14 of the opening 11, there extend two bearing bores 15 and 16. The bearing bores 15 and 16 receive the shaft-s 18 and 19 of the gears 12 for the shafts 18 and 19 to be journaled within the bearing bores. To enclose the gears 12, face plate 20 is provided. The face plate 20 is equal in cross-sectional dimensions to the body 10 and is adapted to be positioned contiguously to said body, and to be attached thereto by means of bolts 21 or the like. The face plate 20 has a blind bore 24 therein to receive the opposite end of the shaft 19; and, the blind bore 24 is coaxial with bore 16 when the face plate 20 is properly positioned. A bore 25 is adjacent the blind bo-re 24; and, the bore 25 extends completely through the face plate 20 to receive the opposite end of the shaft 18, the shaft 18 being properly journaled within the bore 25. The shaft 18 extends outwardly of the face plate 20, and is splined to receive appropriate drive means for the pump.

As is conventional in gear pumps, there is an entrance pump body 10 along the centerline of the pump, to the point between the two gears 12. Likewise, an exit port 28 extends from the point between the gears 12 to the outside of the pump body 10 coaxiay with the entrance port 26. The ports 24 and 26 and the gears 12 are shown in FIG. 2 of the drawings.

Within the bores 15 and 16 of the pump body 10',

l there are bearings 29 and 30 respectively. The bearing 29 is formed as a cylindrical sleeve having an annular flange 31 at its innermost end. The ange 311 is adapted to engage the wall 14 of the opening 11 of the pump body 10 to provide a bot-tom wear surface, while the sleeve of the bearing 29 is received within the bore 15. The bearing 29 is provided with annular oil grooves 32 and 34 on the inside and outside respectively of the bearing. Likewise, the bearing 30 includes a cylindrical portion 35 which `is received within the bore 16 and an annular flange 36 which bears against the wall 14 of the opening 11 of the pump body 10. The bearing 30 has a plurality of longitudinal oil grooves 33 spaced around the inside surface thereof to allow oil to coat the bearing between the bearing 30 and the shaft 19. The dimensions of the bore 16 and the bearing 30 are such that a space is left at the end of each of the bearings 29 and 30; Le., the bearings 29 and 30, and the shafts 18 and 19, terminare short of the bottom wall of the bores 15 and 16. The purpose of this arrangement will be seen later.

The opposite end of the shaft 18 has =a sleeve bearing 38 to journal it within the bore 25. The *bearing 38 has oil grooves 39 and 40, similar to the grooves 32 and 34 of the bearing 39 and an O-ring 37 surrounds the shaft 18 to stop the oil flow. A space 41 is left at the outer end of the bearing 38 and is closed by an outer seal 38a. The opposite end of the shaft 19 is arranged exactly as its end already described; there is a sleeve ybearing 42 received within the blind -bore 24, and a space is left at the end of the blind bore 24.

Within the opening 11, and disposed between the gears 11 and the face plate 20, there is a wear plate 44. The wear plate 44 is best shown in FIGS. 7-9, and is a relatively thick plate with an elongate configuration conforming substantially to the configuration of the opening 11 in the body 10. The wear plate 44 has a pair of holes 45 and 46 to receive the shafts 18 and 19 respectively therethrough. An annular groove surrounds each of the holes 45 and 46 to receive one end of the bearing 38 and 42 to prevent the escape of liuid around the shafts. On the side of the wear plate that is against the gears 12 which provides an upper wear surface, there are cutout portions 48 and 49 to give transverse relief to the oil as the gears intermesh. Likewise, grooves 50 provide transverse relief for the gears lwhen their teeth `are completely meshed.

The opposite side of the wear plate 44 has a peripheral land 49' which receives a exible seal 47. On radii of the holes 45 and 46, there are seal receiving grooves 50 extending from the holes to the periphery. There is a groove 50 on each side of the holes 45 and 46, on diameters thereof; and the grooves 50 are on a diameter transverse to the cavity 11. There is one additional groove 50 on the line connecting the centers of the holes 4S and 46. In FIG. 3 of the drawing, it will be seen that the face plate has complementary grooves 50a to receive the seals 52.

It will thus be seen that the wear plate 44 provides convenient means to seal one side of the gears 12, and to be movable to take up slack due to wear of the face of the face plate 20 or the wear surface of the Ibearings 29 and 30. The wear plate 44 is also movable in accordance with the operating fluid pressure of the pump. The wear plate 44 is therefore pushed against the gears more rmly when the pump is operating at high pressure, and less rmly when the pump is operating at low pressure.

One of the seals to be received `within the grooves S0 is shown in FIG. 5, and includes a substantially rectangular resilient member 52 having an elongate opening 54a, extending vertically into the seal and leaving a closed bottom. The uid system within the pump is so arranged that uid under pressure will enter the elongate opening 54a and exert outward pressure on the seal 52 to seat the seal more firmly, hence the higher the operating pressure of the pump, the greater the sealing of the seals 52.

Referring now to FIGS. l and 2 of the drawings, it will be seen that there is a passage 55 through the pump body 10, communicating with the exit port 28. The passage 55 communicates with a transverse port 56 which includes a check valve 58; and, there is a longitudinal passage 59 which communicates with the port 56. The passage 59 is shown in end view in FIG. 2; and, as shown in FIG. l, the passage 59 connects to the open space at the bottom of the bore 16 in the pump body 10. A passage 60 leads from the open space in the bottom of the bore 16, through the pump body 10, and to the oil groove 32 in the bearing 29. A passage 61 is provided through the bearing 29, to the inner oil groove 34. Another passage 62 is provided in the shaft 18 leading from the oil groove 34 to an axial cavity 64 within the shaft 18.

The check valve 58 as shown is threadedly and removably held within the passage 56 so the check valve 58 can be removed, for cleaning, replacement or the like. A plug 57 closes the outside end of the passage 56.

The shaft 19 has an axial -bore 65 extending completely therethrough, and communicating with the open space in the bottom end of the blind bore 24. The blind bore 24 has a passage y66 extending therefrom to the oil groove 39 in the bearing 38, and passages `68 and 69 connect the passage 66 with the axial cavity 64. Diametrically `across the blind bore 24 from the passage 66, there is a passage 70 leading to the space immediately above the wear plate 44; likewise, a passage 71 leads from the passage 66 to the center of the Wear plate 44. A similar passage 72 leads from the oil groove 39 of the bearing 38, to the wear plate 44.

It will thus be seen that when the pump is operating, fluid will pass from the high pressure exit port 28 through the passageway 55, and into the transverse passageway 56, Fluid will open the check valve 58 to allow the uid to pass through the passageway 59 and to the space in the bottom of the bore 1-6. From the ybore 16, fluid will flow through the passage 60 to the passage 61, thence the axial cavity 64 of the shaft 18. Also, fluid will tlow through the axial cavity 65 of the shaft 19, and int-o the blind -bore 24. 4From the bore 24, uid will ow through the passage 70 to the space immediately above the wear plate 44; uid will ow through the passage `66 and t0 passage 71 to the space immediately above the wear plate 44. Likewise, uid 4will flow from the axial cavity 64 in the shaft 18, through the passage 69, and to the passage 72, to the space immediately above the wear plate 44. If desired, additional volume can be had above the wear plate 44 by providing holes 43 in the face plate 2t). The holes 43 simply allow more oil to collect to assure that there is sufficient oil to allow the pressures to be 'balanced Attention is directed to FIG. 10 which shows the passageways within the face plate 20. In this figure, it will be seen that, in addition to the passageways described above, there are similar passageways 78a and 71a on each side of the ones previously described, giving four circumferentially spaced passageways around the bearing 42, all serving substantially the same functions. Also, there are passageways T to drain the interstices above the lwear plate 44, the passageways T leading to the tank (not shown).

Means are provided to detect the flow of oil into the `bores 15 and 25. From the bore 15 there is a passage 80, which leads to a threadedly inserted tube 81. Between the passage 80 and the central Opening in the tubing 81, there is a restriction 82. There is a branch passage 84, connecting to the passage 80; and, there is a passage communicating with the central opening of the tubing 81. It is contemplated that a dilerential gauge will be placed across the 'branch passages 84 and 85 to detect a difference of pressures between passage 80 and the central opening in the tubing 81. The restriction 82 will cause a difference in pressure between the two points, by which the ow rate through the passages can -be determined. The flow in the passage `80 will remain constant unless the bearing 29 is sufficiently worn for additional uid to flow from the passageway 60 longitudinally of the bearing 29 into the open space at the end of the bore 15.

The bearing 25 has the same arrangement as that just described for the bore 15, including a passageway 86 having restriction 88 leading to the tubing 89. Branch tubes 90 and 91 provide connections for the differential gauge which is not illustrated here. y

From the foregoing description, the operation of the device should be obvious. The pump is rotated by means of the shaft 18 causing a low pressure at the entrance port 26 and a high pressure at the exit port 28. The high pressure fluid will ow from the exit port 28, through the passage 55, and to the passage 56, through the check valve 58, thence to the passageway 59, and to the bore 16. Fluid owing through the passage 60 will lubricate the bearing 29, and will ow through the passage `61, through passage 62, and to the axial cavity 64 of the shaft 18. Fluid will also flow through the axial cavity `65 of the shaft 19 and into the blind bore 24 from -which the fluid will be distributed through the passages 70, 66, and 71 to the space immediately above the wear plate 44 including the holes 43. It will thus be seen that the pressure in both the bore 16 vand the bore 24 will be equal, exerting an equal pressure in both directions on the shaft 19.

Fluid will flow from the axial cavity -64 to the shaft 18 through the passage 69, and to the bearing 38. Fluid will also flow from the passage `66 to the outside of the bearing 38 to the oil groove 34. From the oil groove 34, fluid will flow through the passage 72 to the space immediately above the wear plate 44.

The pressure within the opening 11 of the body 10 is quite low, except at the exit port 28. Since the pressure directed to the upper surface of the wear plate 44, is at the output pressure, and the pressure below the wear plate is less than output pressure, the Wear plate 44 will be urged against the gears 12 to provide a seal.

As long as the bearings 29 and 38 are in good condition the pressure in the cavities 15 and 25 respectively will be substantially constant, giving a substantially constant reading on the gauges. However5 if the bearing 15 becomes excessively w-orn, additional uid will How from the passageway 60 and into the open space at the end of the cavity 15. This will give an increase of pressure in the passageway 80, while the restriction 82 maintains a substantially constant pressure within the tu-bing 81, therelby giving a higher differenti-al pressure reading on the gauge.

In the case of the bearings '38, t-he same is true as that above mentioned; however, if the outer seal 37 is leaking, there will be the additional indication of a fall in pressure twithin the .passage 86. The pump of the present invention therefore provides a very dependable lubricating means for lall portions of the pump that must be lubricated. Due to the equal pressures on both sides of the shaft 19 a good coating of oil will remain in the bearing and will not iiow simply through the bearing.

The bearings 29 and 38 will remain properly lubricated during the operation of the pumps; however, should these bearings become excessively worn, the gauges will indicate the condition of the bearings 'before any severe damage has been done to the pump.

The pressure of the wear plate 44 against the gear 12 will vary with the pressure within the passages 7i), 7l and 72, the wear plate will always give proper sealing at the operating pressure of the pump; however, the wear plate will never be pressed against the gears 12 with more pressure than is needed for the operating pressure of the pump.

It will be realized that pumps such as the gear pump herein described can be operated in either direction. In FIG. 2 of the drawings, it will be seen that there is an identical passageway and check valve leading from the entrance port 26 of the pump providing passage to the passageways 55 and 56 and check valve 58; therefore, no additional description will be given, and the equivalent parts have the same numerals with primes.

It will now be realized that the check valves 58 and 58 are provided so that the iluid will not ow from the passage Se to the passage 56', or from the passage 56' to the passage 56, thus, there will be no interference between the two sets of passageways.

In other embodiments of the pump it will be desirable to remove the ow detecting means on the bearings 29 and 38 and supply pressure on the bearings toward the gear on the shaft 18. This can be easily accomplished by having the passageway 60 lead to the end of the bore 15 instead of to the groove 32 of the bearing 29, and by providing passage means from the passage 71 to a point just inwardly ofthe O-ring 37 in the bearing 38, a passage, such as the passage 86, would then be directed to the tank of the system. This is shown in broken lines in FIG. 1 of the drawings.

The pump would thus provide lubrication under pressure for all the bearings to assure that they will be suiciently lubricated at all times, and at all operating pressures.

To assure that the wear plate 44 will remain balanced;

-i.e., to prevent canting of the wear plate 44, holes may be provided through the wear plate 44 to allow flow of oil therethrough. In the face plate 20, the blind holes 43 will receive oil and act as a reservoir; therefore, there will be oil under pressure between the Wear plate 44 and the face plate 20 to provide even pressure throughout the surface of the wear plate 44. With this arrangement, the passageway T can be directed to a pressure gauge to read the pressure on the pump, which would be desirable in an installation such as in an automobile or other vehicle.

It will be realized by those skilled in the art, that the particular embodiment of the invention herein disclosed is by way of illustration only, and is meant to be in no way restrictive; therefore, numerous changes may be made and the full use of equivalents resorted to without departing from the spirit or scope of the invention as outlined in the appended claims.

What is claimed as my invention is:

1. A gear pump including a body having an opening, an outlet, and an inlet therein, a pair of intermeshed gears received in said body, a rst shaft and a second shaft, each of said shafts carrying one of said gears, a face plate contiguous with said body and secured thereto to close said opening, a bearing in said body to journal one end ot said iirst shaft, a bearing in said face plate to journal the other end of said first shaft, a bearing in said body to journal one end of said second shaft, a bearing in said face plate to journal the other end of said second shaft, a wear plate slidably carried on said first and second shafts between said gears and said face plate, said wear plate being complementary shaped to ill said opening and deining a pair of apertures therethrough to receive said rst and second shafts, said wear plate defining a plurality of slots disposed about each of its apertures, said face plate deiining a plurality of slots corresponding in size and position with the slots of said wear plate and disposed in juxtaposition therewith to define sealing channels, and a plurality of resilient members slidably received in said sealing channels and sealing said Wear plate with said face plate, said shaft and said housing; said resilient members communicating with said outlet to introduce the uid pressure from said outlet against said resilient members to force said resilient members into said sealing channels.

2. The gear pump of claim 1 wherein said Wear plate defines a central slot extending between its apertures and said face plate denes a slot corresponding in size and position to said central slot and disposed in juxtaposition therewith to dene a sealing channel to receive a resilient member.

3. The gear pump of claim 2 wherein said space defined by each end of said Wear plate, said face plate, said housing and said resilient members is connected to said outlet to introduce the uid pressure from said outlet against said wear plate to force said wear plate against said gears.

4. The gear pump of claim 3 including means to selectively connect said resilient members and said wear plate to said outlet and said inlet to introduce the uid pressure therefrom against said resilient members and said wear plate.

References Cited by the Examiner UNITED STATES PATENTS 2,044,873 6/1936 Beust 103-126 2,444,165 6/1948 Lauck 103-126 2,676,548 4/1954 Lauck l03126 2,682,836 7/1954 Orr 103-126 2,714,856 8/1955 Kane 103-126 2,809,592 10/1957 Miller et al 103-126 2,866,416 12/1958 Oliver l03126 3,150,599 9/1964 Laumont 103-126 DONLEY J. STOCKING, Primary Examiner.

WILBUR I. GOODLIN, MARTIN P. SCHWADRON,

Examiners. 

1. A GEAR PUMP INCLUDING A BODY HAVING AN OPENING, AN OUTLET, AND AN INLET THEREIN, A PAIR OF INTERMESHED GEARS RECEIVED IN SAID BODY, A FIRST SHAFT AND A SECOND SHAFT, EACH OF SAID SHAFTS CARRYING ONE OF SAID GEARS, A FACE PLATE CONTIGUOUS WITH SAID BODY AND SECURED THERETO TO CLOSE SAID OPENING, A BEARING IN SAID BODY TO JOURNAL ONE END OF SAID FIRST SHAFT, A BEARING IN SAID FACE PLATE TO JOURNAL THE OTHER END OF SAID FIRST SHAFT, A BEARING IN SAID BODY TO JOURNAL ONE END OF SAID SECOND SHAFT, A BEARING IN SAID FACE PLATE TO JOURNAL THE OTHER END OF SAID SECOND SHAFT, A WEAR PLATE SLIDABLY CARRIED ON SAID FIRST AND SECOND SHAFTS BETWEEN SAID GEARS AND SAID FACE PLATE, SAID WEAR PLATE BEING COMPLEMENTARY SHAPED TO FILL SAID OPENING AND DEFINING A PAIR OF APERTURES THERETHROUGH TO RECEIVE SAID FIRST 